This disclosure relates generally to social networking systems, and in particular to presenting content items to a social networking system user.
A social networking system allows its users to connect to and communicate with other social networking system users. Users may create profiles on a social networking system that are tied to their identities and include information about the users, such as interests and demographic information. The users may be individuals or entities such as corporations or charities.
A social networking system allows its users to post content to the social networking system for presentation to other social networking system users, allowing the users interact with each other. Examples of content items include stories, photos, videos, and invitations. Additionally, the social networking system typically generates content items describing actions performed by users and identified by the social networking system. For example, a content item is generated when a user of a social networking system checks into a location, shares content posted by another user, or performs any other suitable interaction. The social networking system presents content items describing an action performed by a user is presented to an additional user connected to the user via the social networking system. Typically, the social networking system presents content items to users in a feed in an order based on times when content items are generated or received by the social networking system. For example, a feed chronologically presents content items to a user with more recently generated content items presented in more visible locations when presented to a user.
Over time, a large number of content items may be presented to a user by the social networking system. Certain content items previously presented to a user may be relevant to the user at a time after they were initially presented. For example, content items associated with recurring events such as a birthday or a holiday become relevant to a user each year. However, in conventional social networking systems, a user may expend significant time navigating through multiple content items to identify a previously presented content item.